diff --git a/cmd/Ollie/main.go b/cmd/Ollie/main.go
index 0135975..77a16c6 100644
--- a/cmd/Ollie/main.go
+++ b/cmd/Ollie/main.go
@@ -113,9 +113,14 @@ func agentPath(sid string) string {
 
 // --- session list window ---
 
+type sessionEntry struct {
+	id   string // full UUID
+	name string // display name
+}
+
 type sessionList struct {
 	win     *acme.Win
-	allSIDs []string
+	entries []sessionEntry
 	mu      sync.Mutex
 }
 
@@ -134,42 +139,43 @@ func newSessionList() error {
 }
 
 func (sl *sessionList) refresh() {
-	data, err := read9p("session/idx")
+	fsys := dial9p()
+	fid, err := fsys.Open("session", plan9.OREAD)
 	if err != nil {
-		sl.win.Errf("read idx: %v", err)
+		sl.win.Errf("list sessions: %v", err)
 		return
 	}
+	dirs, err := fid.Dirreadall()
+	fid.Close()
+	if err != nil {
+		sl.win.Errf("list sessions: %v", err)
+		return
+	}
+
 	sl.win.Addr(",")
 	sl.win.Write("data", nil)
 
-	raw := strings.TrimSpace(string(data))
-	if raw == "" {
-		sl.win.Ctl("clean")
-		return
-	}
-
-	lines := strings.Split(raw, "\n")
-	sort.Strings(lines)
-
 	sl.mu.Lock()
-	sl.allSIDs = nil
+	sl.entries = nil
 	var display strings.Builder
-	for _, l := range lines {
-		if s := strings.TrimSpace(l); s != "" {
-			id, rest, _ := strings.Cut(s, "\t")
-			sl.allSIDs = append(sl.allSIDs, id)
-			short := id
-			if idx := strings.IndexByte(id, '-'); idx > 0 {
-				short = id[:idx]
-			}
-			display.WriteString(short)
-			if rest != "" {
-				display.WriteByte('\t')
-				display.WriteString(rest)
-			}
-			display.WriteByte('\n')
+	for _, d := range dirs {
+		if d.Mode&plan9.DMDIR == 0 {
+			continue
 		}
+		id := d.Name
+		name := id
+		if d, err := read9p("session/" + id + "/name"); err == nil {
+			if n := strings.TrimSpace(string(d)); n != "" {
+				name = n
+			}
+		}
+		sl.entries = append(sl.entries, sessionEntry{id: id, name: name})
+		display.WriteString(name)
+		display.WriteByte('\n')
 	}
+	sort.Slice(sl.entries, func(i, j int) bool {
+		return sl.entries[i].name < sl.entries[j].name
+	})
 	sl.mu.Unlock()
 
 	sl.win.Write("body", []byte(display.String()))
@@ -183,13 +189,9 @@ func (sl *sessionList) resolveFullSID(text string) string {
 	}
 	sl.mu.Lock()
 	defer sl.mu.Unlock()
-	for _, sid := range sl.allSIDs {
-		short := sid
-		if idx := strings.IndexByte(sid, '-'); idx > 0 {
-			short = sid[:idx]
-		}
-		if short == text || sid == text {
-			return sid
+	for _, e := range sl.entries {
+		if e.name == text || e.id == text {
+			return e.id
 		}
 	}
 	return ""
@@ -252,18 +254,11 @@ func openChat(sid string) {
 		log.Printf("open chat %s: %v", sid, err)
 		return
 	}
-	short := sid
-	if idx := strings.IndexByte(sid, '-'); idx > 0 {
-		short = sid[:idx]
-	}
-	winName := "ollie/sessions/" + short
-	if data, err := read9p("session/idx"); err == nil {
-		for _, line := range strings.Split(string(data), "\n") {
-			fields := strings.Split(line, "\t")
-			if len(fields) >= 3 && fields[0] == sid {
-				winName = fields[2] + "/+Ollie"
-				break
-			}
+	winName := "ollie/sessions"
+	if data, err := read9p("session/" + sid + "/name"); err == nil {
+		name := strings.TrimSpace(string(data))
+		if name != "" {
+			winName = name + "/+Ollie"
 		}
 	}
 	w.Name("%s", winName)
diff --git a/fs/session/create.go b/fs/session/create.go
index 6ddf9a0..b353c67 100644
--- a/fs/session/create.go
+++ b/fs/session/create.go
@@ -70,9 +70,12 @@ func Create(rs *rootState, args []string) (string, error) {
 		}
 	}
 
-	sessID := name
-	if sessID == "" {
-		sessID = coresession.NewSessionID()
+	sessID := coresession.NewSessionID()
+	if name == "" {
+		name = sessID
+		if idx := strings.IndexByte(sessID, '-'); idx > 0 {
+			name = sessID[:idx]
+		}
 	}
 
 	rs.mu.RLock()
@@ -246,6 +249,7 @@ func Create(rs *rootState, args []string) (string, error) {
 
 	sessionCtx, sessionCancel := context.WithCancel(rs.cfg.Ctx)
 	sess := NewSession(sessID, core, sessionCtx, sessionCancel)
+	sess.SetName(name)
 	sessPtr = sess
 	sess.AgentLog = al
 	sess.proc = proc
diff --git a/fs/session/files.go b/fs/session/files.go
index 8e156ff..c7d897b 100644
--- a/fs/session/files.go
+++ b/fs/session/files.go
@@ -113,6 +113,18 @@ func (h *sessionHelper) fileSpec(name string, mode os.FileMode) FileSpec {
 	fs := FileSpec{Name: name, Mode: mode}
 
 	switch name {
+	case "id":
+		fs.Read = func() ([]byte, error) { return []byte(h.sess.id), nil }
+	case "name":
+		fs.Read = func() ([]byte, error) { return []byte(h.sess.Name()), nil }
+		fs.Write = func(data []byte) error {
+			newName := strings.TrimSpace(string(data))
+			if newName == "" {
+				return nil
+			}
+			h.sess.SetName(newName)
+			return nil
+		}
 	case "env":
 		fs.Read = func() ([]byte, error) { return []byte(h.envContent()), nil }
 	case "ctl":
diff --git a/fs/session/perm.go b/fs/session/perm.go
index c64c8a1..691be06 100644
--- a/fs/session/perm.go
+++ b/fs/session/perm.go
@@ -90,6 +90,8 @@ var Perms = map[string]Perm{
 			"toolsrv.loaded": 0444,
 			"toolsrv.rev":    0444,
 			"tools":        0666,
+			"name":         0666,
+			"id":           0444,
 		},
 	},
 }
diff --git a/fs/session/persist.go b/fs/session/persist.go
index be8a33c..e675a33 100644
--- a/fs/session/persist.go
+++ b/fs/session/persist.go
@@ -39,33 +39,19 @@ func KillFromRoot(root *Tree, id string) {
 	Kill(state(root), id)
 }
 
-// Rename renames a session.
+// Rename renames a session by setting its Name. The immutable ID stays unchanged.
 func Rename(rs *rootState, old, new string) error {
-	rs.mu.Lock()
+	rs.mu.RLock()
 	sess, ok := rs.sessions[old]
+	rs.mu.RUnlock()
 	if !ok {
-		rs.mu.Unlock()
 		return fmt.Errorf("session not found: %s", old)
 	}
-	if _, exists := rs.sessions[new]; exists {
-		rs.mu.Unlock()
-		return fmt.Errorf("session already exists: %s", new)
-	}
 	if sess.Core.Agent().IsRunning() {
-		rs.mu.Unlock()
 		return fmt.Errorf("cannot rename while agent is running")
 	}
 
-	if err := sess.Core.SetSessionID(new); err != nil {
-		rs.mu.Unlock()
-		return err
-	}
-
-	sess.id = new
-	rs.sessions[new] = sess
-	delete(rs.sessions, old)
-	rs.mu.Unlock()
-
+	sess.SetName(new)
 	rs.cfg.Log.Info("renamed session %s -> %s", old, new)
 	broadcastEvents()
 	return nil
diff --git a/fs/session/root.go b/fs/session/root.go
index efaac96..4d4621d 100644
--- a/fs/session/root.go
+++ b/fs/session/root.go
@@ -486,17 +486,18 @@ func buildIndex(rs *rootState) []byte {
 		ids = append(ids, id)
 	}
 	sort.Strings(ids)
-	for _, id := range ids {
-		sess := rs.sessions[id]
-		sess.mu.RLock()
-		st := sess.Core.Agent().State()
-		cwd := sess.Core.CWD()
-		be := sess.Core.Agent().BackendName()
-		model := sess.Core.Agent().ModelName()
-		ag := sess.Core.Agent().Name()
-		sess.mu.RUnlock()
-		fmt.Fprintf(&sb, "%s\t%s\t%s\t%s\t%s\t%s\n", id, st, cwd, be, model, ag)
-	}
+for _, id := range ids {
+			sess := rs.sessions[id]
+			sess.mu.RLock()
+			st := sess.Core.Agent().State()
+			cwd := sess.Core.CWD()
+			be := sess.Core.Agent().BackendName()
+			model := sess.Core.Agent().ModelName()
+			ag := sess.Core.Agent().Name()
+			name := sess.name
+			sess.mu.RUnlock()
+			fmt.Fprintf(&sb, "%s\t%s\t%s\t%s\t%s\t%s\n", name, st, cwd, be, model, ag)
+		}
 	rs.mu.RUnlock()
 	return []byte(sb.String())
 }
diff --git a/fs/session/types.go b/fs/session/types.go
index ab259af..9c7c816 100644
--- a/fs/session/types.go
+++ b/fs/session/types.go
@@ -15,7 +15,8 @@ import (
 // Agent-scoped state (log, plan, etc.) lives in AgentLog.
 type Session struct {
 	mu         sync.RWMutex
-	id         string
+	id         string // immutable UUID, set at creation, never changes
+	name       string // mutable friendly name, defaults to id
 	uname      string // immutable user principal (numeric UID), set at creation
 	Core       *session.Session
 	SessionCtx context.Context
@@ -53,7 +54,11 @@ func NewAgentLog(remote string) *AgentLog {
 }
 
 func NewSession(id string, core *session.Session, ctx context.Context, cancel context.CancelFunc) *Session {
-	sess := &Session{id: id, Core: core, SessionCtx: ctx, cancel: cancel}
+	name := id
+	if idx := strings.IndexByte(id, '-'); idx > 0 {
+		name = id[:idx]
+	}
+	sess := &Session{id: id, name: name, Core: core, SessionCtx: ctx, cancel: cancel}
 	return sess
 }
 
@@ -92,6 +97,16 @@ func (sess *Session) InvalidateModelsCache() {
 
 func (sess *Session) RunnableID() string { return sess.id }
 func (sess *Session) Uname() string      { return sess.uname }
+func (sess *Session) Name() string {
+	sess.mu.RLock()
+	defer sess.mu.RUnlock()
+	return sess.name
+}
+func (sess *Session) SetName(name string) {
+	sess.mu.Lock()
+	defer sess.mu.Unlock()
+	sess.name = name
+}
 
 func (sess *Session) Cancel() {
 	sess.cancel()